FACEBOOK:
Most skilled Deaf signers do this sign by spelling the letters FB.

FACEBOOK (2)
(variation)
This version is a pun that combines aspects of the signs for BOOK
and FACE:
[Insert video and jpegs here.]
Signing notes: As of early 2010
this version is for the most part simply an amusing neologism (emerging
sign). It will be
interesting to track this version and see if it will become more widely
used or if it will fade out over time. (Time will tell.)
Also see:
BOOK
Also see: FACE